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At least 1,153 records · Page 64Linked to original sources
PubMed2006

Changes in white matter diffusion anisotropy in adolescents born prematurely.

Being born with very low birth weight (VLBW, birth weight<or=1500 g) or small for gestational age (SGA) carries an increased risk of cerebral white matter damage. The reduced cognitive and motor skills these two groups exhibit suggest that the early injuries to white matter persist into adolescence. White matter integrity was assessed using voxel-wise statistical analysis of fractional anisotropy (FA) maps between three groups of adolescents at age 15; the VLBW group (n=34), the SGA group (n=42) and a control group with normal birth weight (n=47). The FA maps were normalized to a study specific template and group differences were assessed using an analysis of covariance with gender as a confounder (FDR-corrected P<0.05). The main finding is that the VLBW group has significantly reduced FA values in several white matter regions, including the corpus callosum, internal capsule and superior fasciculus compared to the control group. Some of the observed reduction in anisotropy, particularly that observed in the corpus callosum, may have been caused by inaccurate spatial normalization, but this can only explain 30% of the area with reduced anisotropy. Analysis of the eigenvalues of the diffusion tensor show that the reduced FA values in the VLBW group is primarily due to an increase in the two lowest eigenvalues of the diffusion tensor. We speculate that this may be caused by reduced myelination. For the SGA group, we find no statistically significant differences in anisotropy compared to the control group.

Adolescent↗
PubMed2005

Minocycline attenuates lipopolysaccharide-induced white matter injury in the neonatal rat brain.

Our previous studies have shown that intracerebral administration of endotoxin, lipopolysaccharide (LPS), induces selective white matter injury and hypomyelination in the neonatal rat brain and that the LPS-induced brain injury is associated with activation of microglia. To test the hypothesis that inhibition of microglial activation may protect against LPS-induced white matter injury, we examined roles of minocycline, a putative suppressor of microglial activation, on LPS-induced brain injury in the neonatal rat. A stereotactic intracerebral injection of LPS (1 mg/kg) was performed in postnatal day 5 Sprague-Dawley rats and control rats were injected with sterile saline. Minocycline (45 mg/kg) was administered intraperitoneally 12 h before and immediately after LPS injection and then every 24 h for 3 days. Inflammatory responses, activation of microglia and brain injury were examined 1 and 3 days after LPS injection. LPS injection resulted in brain injury in selective brain areas, including bilateral ventricular enlargement, cell death at the sub- and periventricular areas, loss of O4+ and O1+ oligodendrocyte (OL) immunoreactivity and hypomyelination, as indicated by decreased myelin basic protein immunostaining, in the neonatal rat brain. Minocycline administration significantly attenuated LPS-induced brain injury in these rat brains. The protective effect of minocycline was associated with suppressed microglial activation as indicated by the decreased number of activated microglial cells following LPS stimulation and with consequently decreased elevation of interleukin 1beta and tumor necrosis factor-alpha concentrations induced by LPS and a reduced number of inducible nitric oxide synthase expressing cells. Protection of minocycline was also linked with the reduction in LPS-induced oxidative stress, as indicated by 4-hydroxynonenal positive OLs. The overall results suggest that reduction in microglial activation may protect the neonatal brain from LPS-induced white matter injury and inhibition of microglial activation might be an effective approach for the therapeutic treatment of infection-induced white matter injury.

Animals↗
PubMed2005

GABAergic neurones in the rat periaqueductal grey matter express alpha4, beta1 and delta GABAA receptor subunits: plasticity of expression during the estrous cycle.

Immunoreactivity for alpha4, beta1 and delta GABAA receptor subunits on neurones in the periaqueductal gray matter was investigated at different stages of the estrous cycle in Wistar rats. Immunostaining for alpha4, beta1 and delta GABAA receptor subunits was present on neurones throughout the periaqueductal gray matter. The numbers of subunit-immunoreactive neurones remained constant during the early phases of the estrous cycle (proestrus to early diestrus) but increased significantly in late diestrus. Dual immunolabeling for the GABA synthesizing enzyme glutamic acid decarboxylase revealed that almost 90% of the subunit-positive cells contained immunoreactivity for glutamic acid decarboxylase. During the early phases of the estrous cycle (proestrus to early diestrus), approximately one third of the glutamic acid decarboxylase-positive population co-localized alpha4, beta1 and delta GABAA receptor subunits. When the number of subunit positive cells increased during late diestrus, the proportion of the glutamic acid decarboxylase-containing population that expressed alpha4, beta1 and delta GABAA receptor subunits almost doubled. We propose that GABAA receptors with the alpha4beta1delta configuration are expressed by GABAergic neurones in the periaqueductal gray matter and that the numbers of cells expressing these subunits are increased in late diestrus in line with falling plasma progesterone levels. Changes in GABAA receptor expression may lead to changes in the excitability of the neural circuitry in the periaqueductal gray matter.

Animals↗
PubMed2006

Erythropoietin-mediated preservation of the white matter in rat spinal cord injury.

We investigated the effect of a single administration of recombinant human erythropoietin (rhEPO) on the preservation of the ventral white matter of rats at 4 weeks after contusive spinal cord injury (SCI), a time at which functional recovery is significantly improved in comparison to the controls [Gorio A, Necati Gokmen N, Erbayraktar S, Yilmaz O, Madaschi L, Cichetti C, Di Giulio AM, Enver Vardar E, Cerami A, Brines M (2002) Recombinant human erythropoietin counteracts secondary injury and markedly enhances neurological recovery from experimental spinal cord trauma. Proc Natl Acad Sci U S A 99:9450-9455; Gorio A, Madaschi L, Di Stefano B, Carelli S, Di Giulio AM, De Biasi S, Coleman T, Cerami A, Brines M (2005) Methylprednisolone neutralizes the beneficial effects of erythropoietin in experimental spinal cord injury. Proc Natl Acad Sci U S A 102:16379-16384]. Specifically, we examined, by morphological and cytochemical methods combined with light, confocal and electron microscopy, i) myelin preservation, ii) activation of adult oligodendrocyte progenitors (OPCs) identified for the expression of NG2 transmembrane proteoglycan, iii) changes in the amount of the chondroitin sulfate proteoglycans neurocan, versican and phosphacan and of their glycosaminoglycan component labeled with Wisteria floribunda lectin, and iv) ventral horn density of the serotonergic plexus as a marker of descending motor control axons. Injured rats received either saline or a single dose of rhEPO within 30 min after SCI. The results showed that the significant improvement of functional outcome observed in rhEPO-treated rats was associated with a better preservation of myelin in the ventral white matter. Moreover, the significant increase of both the number of NG2-positive OPCs and the labeling for Nogo-A, a marker of differentiated oligodendrocytes, suggested that rhEPO treatment could result in the generation of new myelinating oligodendrocytes. Sparing of fiber tracts in the ventral white matter was confirmed by the increased density of the serotonergic plexus around motor neurons. As for chondroitin sulfate proteoglycans, only phosphacan, increased in saline-treated rats, returned to normal levels in rhEPO group, probably reflecting a better maintenance of glial-axolemmal relationships along nerve fibers. In conclusion, this investigation expands previous studies supporting the pleiotropic neuroprotective effect of rhEPO on secondary degenerative response and its therapeutic potential for the treatment of SCI and confirms that the preservation of the ventral white matter, which contains descending motor pathways, may be critical for limiting functional deficit.

Animals↗
PubMed2006

Prefrontal but not temporal grey matter changes in males with first-episode schizophrenia.

INTRODUCTION: Changes of brain morphology are now considered as a part of the pathology of schizophrenia. Voxel-based morphometry may be used to study regional changes of the grey matter in the whole brain. It is advantageous to study first-episode patients to prevent the influence of many possible biasing factors when trying to identify primary pathological processes underlying the manifestation of the illness. OBJECTIVE: To investigate regional grey matter changes in the first-episode schizophrenia patients. METHODS: Optimized voxel-based morphometry was used to detect changes in grey matter volume in 22 patients with first-episode schizophrenia compared with 18 healthy volunteers of comparable age, gender and handedness. RESULTS: The first-episode schizophrenia group had significantly reduced grey matter volume in the prefrontal cortex (inferior and middle prefrontal gyrus, cingulate gyrus). We identified no differences in the temporal cortex. CONCLUSION: Our data support the theoretical assumption that prefrontal dysfunction underlines the primary pathology and clinical manifestation of schizophrenia. We are inclined to explain the differences in the pattern of morphological changes reported in other first-episode studies--especially the lack of changes in the temporal cortex--by heterogeneity of schizophrenia, potential progression and antipsychotic medication effect.

Adult↗
PubMed2004

Gray matter abnormalities in paranoid schizophrenia and their clinical correlations.

Numerous imaging studies have shown structural brain abnormalities in schizophrenia. Recently, voxel-based morphometry enabled whole brain analysis beyond the regions of interest (ROI). Regional gray matter concentrations of magnetic resonance (MR) images from 35 patients with paranoid schizophrenia were compared with those from 35 age- and sex-matched controls, and their clinical correlations were explored using voxel-based morphometry. Gray matter concentrations in the patients were significantly reduced in the left insular and dorsolateral prefrontal regions, and bilaterally in the medial frontal, anterior cingulate, inferior frontal and superior temporal regions. On the other hand, gray matter concentrations in the bilateral cerebellum and right striatum were significantly increased in the patients compared with controls. A negative correlation between the score for the severity of 'lack of insight and judgment' and gray matter concentrations in the left posterior and right anterior cingulate and bilateral inferior temporal regions including the lateral fusiform gyri was found. These results suggest the important roles of the paralimbic structures in the pathophysiology of schizophrenia and the involvement of the perceptual and monitoring systems in the mechanism of insight.

Adult↗
PubMed2005

The micro-distribution of carbonaceous matter in the Murchison meteorite as investigated by Raman imaging.

The carbonaceous Murchison chondrite is one of the most studied meteorites. It is considered to be an astrobiology standard for detection of extraterrestrial organic matter. Considerable work has been done to resolve the elemental composition of this meteorite. Raman spectroscopy is a very suitable technique for non-destructive rapid in situ analyses to establish the spatial distribution of carbonaceous matter. This report demonstrates that Raman cartography at a resolution of 1 microm2 can be performed. Two-dimensional distribution of graphitised carbon, amorphous carbonaceous matter and minerals were obtained on 100 microm2 maps. Maps of the surface of native stones and of a powdered sample are compared. Graphitic and amorphous carbonaceous domains are found to be highly overlapping in all tested areas at the surface of the meteorite and in its interior as well. Pyroxene, olivine and iron oxide grains are embedded into this mixed carbonaceous material. The results show that every mineral grain with a size of less than a few microm2 is encased in a thin carbonaceous matrix, which accounts for only 2.5 wt.%. This interstitial matter sticks together isolated mineral crystallites or concretions, including only very few individualized graphitised grains. Grinding separates the mineral particles but most of them retain their carbonaceous coating. This Raman study complements recent findings deduced from other spatial analyses performed by microprobe laser-desorption laser-ionisation mass spectrometry (microL2MS), transmission electron microscopy (TEM) and scanning transmission X-ray microscopy (STXM).

Carbon↗
PubMed2006

The effects of anthropogenic organic matter inputs on stable carbon and nitrogen isotopes in organisms from different trophic levels in a southern Mediterranean coastal area.

Stable isotope ratios were used to determine the impact of anthropogenically derived organic matter from onshore and offshore fish farming and a sewage outfall on organisms at different trophic levels (primary producers and consumers) on the south-east coast of Sicily (Italy, Mediterranean). Representative macroalgae and consumers were collected in three sampling locations: "Impact" and two putative "Controls" sited to the north of the impacted location. While delta(13)C values of both organic matter sources and consumers varied little between locations, delta(15)N spatial variability was higher and delta(15)N was shown to be a good descriptor of organic enrichment and uptake of anthropogenically derived material within coastal food webs. Isotopic data were analysed using a multivariate approach. Organic matter sources and benthic components were more sensitive to pollution than nektobenthic species and revealed that the effects of anthropogenic activities seem to be detectable over a wide area. The study site is characterised by wide waste dispersal, which brings a reduction in impact in the area directly affected by organic matter inputs and enlarges the area of moderate impact.

Alismatales↗
PubMed2006

Genotoxicity induced by fine urban air particulate matter in the macrophages cell line RAW 264.7.

Recent studies support a participation of fine airborne particulate matter (PM) with an aerodynamic diameter less than 2.5 microm in the effects of air pollutants on health. Particulate matter was collected in an urban area of L'Aquila during the winter 2004. Fine particulate samples were analyzed by X-ray photoelectron spectroscopy (XPS) to determine the chemical inventory of the aerosol particle surfaces and to evaluate the weight of characteristic functional groups of the most frequent carbon-containing organic pollutant compounds (C-C/C-H, C-O/C-N, C=O, COOH). The most important contributor to the mass of fine particulate matter was carbon. The overall purpose of this work was to determine the in vitro toxicity and genotoxicity of fine PM in cultured macrophages (RAW 264.7 cells) since the biological target of inhaled PM are the pulmonary epithelium and resident macrophages. In parallel in vitro toxicity assays were used including cell viability and apoptosis. Genotoxicity was evaluated by the micronucleus (MN) assay. The viability of macrophages was assessed by the MTT method; apoptosis by an ELISA test for programmed cell death (PCD) was determined after RAW 264.7 cells treatment. Concentration of 1, 3 and 10 microg/cm2 of fine particles induced micronuclei in a dose-dependent manner. We also compared the effects of fine PM with those of fine carbon black particles (CB) in similar doses. Fine carbon black particles were consistently less genotoxic than the fine atmospheric particles, suggesting that the contaminants adsorbed on them (i.e. carbon-containing organic compounds in addition to metal oxides and metal salts) are involved in genotoxicity. Fine PM reduced cellular proliferation. Overall, the results presented here demonstrate the utility of in vitro tests in mouse cells for testing genotoxicity of urban air particulate matter.

Air Pollutants↗
PubMed2005

Changes in organic matter composition during composting of two digested sewage sludges.

Changes in the chemical and chemical-structural composition of the organic matter of two different sewage sludges (aerobic and anaerobic) mixed with sawdust (1:1 and 1:3, v/v) during composting were determined by monitoring chemical and microbiological parameters as well as by pyrolysis-gas chromatography. Composting was carried out in periodically turned outdoor piles, which were sampled for analysis 1, 30, 60 and 90 days after the beginning of the composting process. Both volatile organic matter and the water soluble C fraction decreased during composting, indicating that the more labile C fractions are mineralized during the process. Microbial activity as measured by microbial respiration (CO(2) evolved from compost samples during incubation) also decreased with composting, reflecting the more stable character of the resulting compost. No major differences were observed between the four composts studied as regards their chemical-structural characteristics. The acetonitrile, acetic acid and phenol pyrolytic fragment tended to increase with composting. Although the final composts were more aromatic in nature than the starting materials, a low degree of humification was observed in all four composts studied, as determined by their high proportion of polysaccharides and alkyl compounds. For this reason, the relationship between pyrolytic fragments, such as benzene/toluene or benzene+toluene/pyrrol+phenols, which are used as indices of humification for soil organic matter, are not of use for such poorly evolved sludge composts; instead, ratios that involve carbohydrate derivatives and aromatic compounds, such as furfural+acetic/benzene+toluene or acetic/toluene, are more sensitive indices for reflecting the transformations of these materials during composting. Both the chemical and microbiological parameters and pyrolytic analysis provided valuable information concerning the nature of the compost's organic matter and its changes during the composting process.

Aerobiosis↗
PubMed2004

The effect of pretreatment to ultrafiltration of biologically treated sewage effluent: a detailed effluent organic matter (EfOM) characterization.

Ultrafiltration alone can remove only a portion of the effluent organic matter (EfOM) from biologically treated sewage effluent (BTSE). Use of pretreatment not only improves the EfOM removal but also reduces the membrane fouling. In this research, NTR 7410 ultrafiltration membrane was employed to remove EfOM from BTSE. Different pretreatments namely FeCl(3) flocculation and powder activated carbon adsorption were evaluated. The highest removal of organic matter was observed when flocculation followed by adsorption was used as pretreatment. The flocculation and adsorption removed 68.5% and 71.4% of hydrophobic organics, respectively. The molecular weight (MW) of the EfOM in BTSE ranged from 300 to about 400000 Da. After the flocculation pretreatment, the majority of large MW organic matter was removed. The pretreatment of the flocculation followed by adsorption led to very high removal of both small and large organic matter. Further, this pretreatment led to practically no filtration flux decline.

Filtration↗
PubMed2004

Removal and transformation of recalcitrant organic matter from stabilized saline landfill leachates by coagulation-ozonation coupling processes.

The Bordo Poniente sanitary landfill in Mexico City currently receives 11,500 ton/day of solid wastes. The landfill has been in operation since 1985, in what was formerly Texcoco Lake, now a dried-up lakebed. The physico-chemical characteristics of the leachate generated by this particular landfill are altered by the incorporation of freatic saline water present in the area. This paper reports the results from a study evaluating coagulation and ozonation as alternative processes for removing and transforming recalcitrant organic matter from stabilized saline landfill leachate. Coagulation with ferric sulfate was found to remove up to 67% of COD and 96% of leachate color. The remaining 33% COD was removed with ozone. Recalcitrant organic matter removal by ozonation is limited by the reaction kinetic due mainly to ozone's low reactivity with the organic compounds present in the leachates (amines, amides, alcohols, aliphatic compounds, and carboxylic acids). However, ozone contributes greatly to changing the recalcitrant characteristics of organic matter. Leachate biodegradability was found to be significantly enhanced through ozonation: BOD(5) values reach 265%, and the BOD(5)/COD ratio increases from 0.003 to 0.015. Infrared analysis of ozonated leachates shows that the main by-products of recalcitrant organic matter ozonation are an increase in the hydroxyl and carboxylic groups, and the presence of aldehydes groups.

Hydrogen-Ion Concentration↗
PubMed2006

Performance of experimental horizontal subsurface flow constructed wetlands fed with dissolved or particulate organic matter.

In this study, the effect of the influent type of organic matter (dissolved or particulate) on the efficiency of two experimental horizontal subsurface flow constructed wetlands (SSF CWs) was investigated. The SSF CWs' surface area was 0.54 m(2) and the water depth was 0.3m. They were monitored for a period of 9 months. One of the SSF CWs was fed with dissolved organic matter (glucose, assumed to be readily biodegradable), and the other with particulate organic matter (starch, assumed to be slowly biodegradable). The removal efficiency of the systems was tested at different hydraulic retention times (HRTs) in the presence or absence of sulphate. The removal efficiency of the COD was not different in the two systems, reaching eliminations of around 85% in the presence of sulphates and around 95% in their absence. Ammonia N removal was low in the two SSF CWs; the system fed with glucose generally had statistically significant higher removal (45%) than the one fed with starch (40%). Ammonia N removal was more affected by the HRT than by the presence or absence of sulphates. Hydraulic conductivity measurements showed that it was lower near the inlet of the SFF CW fed with glucose, probably connected to the fact that there was a more substantial development of the biofilm. The results of this study suggest that SSF CWs are not sensitive to the type of organic matter in the influents, whether it is readily (like glucose) or slowly (like starch) biodegradable, for the removal of COD.

Ammonia↗
PubMed2002

Signature tau neuropathology in gray and white matter of corticobasal degeneration.

Corticobasal degeneration (CBD) is an adult-onset progressive neurodegenerative disorder characterized by L-dopa-resistant rigidity, focal cortical deficits, and variable dementia. The neuropathological hallmark of CBD is the deposition of filamentous inclusions in neurons and glia composed of hyperphosphorylated tau with only four microtubule-binding repeats (4R-tau). To characterize the regional burden of tau pathology in CBD, we studied 12 brains with the neuropathological diagnosis of CBD using biochemical and histochemical techniques. Eleven brain regions were evaluated including gray and white matter from frontal, parietal, temporal, and occipital lobes and cerebellum as well as basal ganglia. Although the distribution of tau pathology was variable, neuropathological and biochemical data showed a similar burden of tau abnormalities in frontal, temporal, and parietal lobes and basal ganglia of both hemispheres. This included abundant, sarkosyl-insoluble 4R-tau in both gray and white matter of two or more of these cortical regions and basal ganglia, and to a lesser extent, cerebellar white matter. The insoluble tau pathology in gray and white matter showed overlapping but distinct phosphorylated epitopes suggesting cell-type and subcellular localization (ie, cell bodies versus cell processes)-specific differences in tau phosphorylation. In contrast, soluble tau was composed of normal 4R/3R-tau ratios indicating no gross abnormality in tau splicing. Thus, although clinically heterogeneous, CBD is a distinct lobar and basal ganglionic tauopathy with selective aggregation of 4R-tau.

Aged↗
PubMed2002

Decreased gray matter concentration in the insular, orbitofrontal, cingulate, and temporal cortices of cocaine patients.

BACKGROUND: Structural deficiencies within limbic and prefrontal regions may contribute to the characteristic drug-seeking and drug-taking behaviors that prevail in persons dependent on cocaine. To date, a focal structural analysis of the brains of cocaine patients has not been undertaken. METHODS: We used voxel based morphometry in conjunction with statistical parametric mapping on the structural magnetic resonance images of cocaine-dependent (n = 13) and cocaine-naive individuals (n = 16) to assess differences between the two groups in gray and white matter concentration. RESULTS: We report a decrease in gray matter concentration in the ventromedial orbitofrontal, anterior cingulate, anteroventral insular, and superior temporal cortices of cocaine patients in comparison to controls (p <.01 corrected for multiple comparisons). The average percentage decrease in gray matter concentration within a region ranged from 5% to 11%. White matter concentration did not differ between groups. CONCLUSIONS: We conclude that the brains of cocaine patients are structurally dissimilar from those of nondrug-using controls. The differences were detected in regions involved in decision-making, behavioral inhibition and assignation of emotional valence to environmental stimuli and, hence, may contribute to some of the behavioral deficits characteristic of chronic cocaine users.

Adult↗
PubMed2002

Axonal damage and demyelination in the white matter after chronic cerebral hypoperfusion in the rat.

Cerebral white matter (WM) lesions are observed frequently in human ischemic cerebrovascular disease and have been thought to contribute to cognitive impairment. This type of lesion can be experimentally induced in rat brains under chronic cerebral hypoperfusion by the permanent occlusion of both common carotid arteries. However, it remains uncertain whether chronic ischemia can damage both the gray and white matter, and whether it can induce demyelination with or without axonal damage. Therefore, we examined axonal damage using immunohistochemistry for the amyloid beta/A4 precursor protein (APP), chromogranin A (CgA) and demyelination using immunohistochemistry for the encephalitogenic peptide (EP) in this model. Severe WM lesions such as vacuolation and the loss of nerve fibers appeared in the optic nerve and optic tract after 3 days of ligation, and less intense changes were observed in the corpus callosum, internal capsule, and fiber bundles of the caudoputamen after 7 days with Klüver-Barrera and Bielschowsky staining. These WM lesions persisted even after 30 days. The APP, CgA, and EP-immunopositive fibers increased in number from 1 to 30 days after the ligation in the following WM regions: the optic nerve, optic tract, corpus callosum, internal capsule, and fiber bundles of the caudoputamen. In contrast, only a few APP, CgA, or EP-immunopositive fibers were detected in the gray matter regions, including the cerebral cortex and hippocampus. These results indicate that the WM is more susceptible to chronic cerebral hypoperfusion than the gray matter, with an involvement of both axonal and myelin components. Furthermore, immunohistochemistry for APP, CgA, and EP is far superior to routine histological staining in sensitivity and may become a useful tool to investigate WM lesions caused by various pathoetiologies.

Amyloid beta-Protein Precursor↗
PubMed1998

Dose-dependent, protective effect of FK506 against white matter changes in the rat brain after chronic cerebral ischemia.

Neuroprotective effects of immunosuppressive agents have been shown in cerebral ischemia. To investigate the role of immunosuppressive agents in chronic cerebral ischemia and to design a drug protocol with safe therapeutic windows, we examined the effects of FK506, a potent immunosuppressive agent, on chronic cerebral ischemia. Both common carotid arteries were ligated in 73 male Wistar rats. Fifty-eight of these rats received a chronic injection of FK506 (0.2, 0.5, 1.0 mg/kg) and the remaining 15 received a vehicle solution injection. Microglia/macrophage was investigated with immunohistochemistry for leukocyte common antigen and major histocompatibility complex, and astroglia was examined with glial fibrillary acidic protein as markers. White matter rarefaction and the number of immunopositive glial cells were assessed from 7 to 30 days after the ligation. In the vehicle-treated animals, there was persistent and extensive activation of the microglia/macrophages and astroglia in the white matter, including the optic nerve, optic tract, corpus callosum, internal capsule, anterior commissure and traversing fiber bundles of the caudoputamen. In the FK506-treated rats, the number of activated microglia/macrophages was significantly reduced in a dose-dependent manner (p<0.01) as compared to the vehicle-treated rats. Rarefaction of the white matter was also inhibited by FK506 in a dose-dependent manner (p<0. 01). Thus, a clinically-relevant dosage of FK506 attenuated both glial activation and white matter changes in chronic cerebral ischemia in the rat. These results indicate a potential use for FK506 in cerebrovascular diseases.

Animals↗
PubMed1996

Sub-cortical white-grey matter contrast on MRI as a quantitative marker of diffuse HIV-related parenchymal abnormality.

White matter change occurs in human immunodeficiency virus (HIV) encephalopathy, which may be difficult to assess subjectively especially in the early stages of disease. This study applies a quantitative approach to the assessment of this finding. Sixty-three HIV seropositive subjects, 47 seronegative blood donors and 17 seronegative homosexual men underwent axial T2 weighted MRI of the brain at 1.5T. Quantitative analysis was performed by obtaining the pixel contrast between parieto-occipital white matter and head of caudate grey matter (Cwg). Highest values of Cwg were found in a subgroup of subjects with AIDS who had diffuse/patchy white matter abnormalities and atrophy on qualitative image assessment. Statistically significant differences were found in Cwg between subjects with high (> or = 200 x 10(6)/I) and low (< 200 x 10(6)/I) CD4 lymphocyte counts (P < 0.05) and between subjects with and without HIV-1 associated cognitive/motor complex (P < 0.05). This technique provides an objective measure of diffuse HIV-related parenchymal abnormality seen on T2 weighted MRI.

AIDS Dementia Complex↗